The new 12-inch MacBook is the pinnacle of Apple's manufacturing perfection for computers, despite people's complaints about it bearing just one USB-C port. Even if you hate the keyboard (and I've gotten used to it), it works precisely as advertised.
Apple's hardware engineering all feeds back across its product lines. While other firms have distinct divisions that become "silos," in which there is very little cross-product interaction, one of Steve Jobs' key managerial missions was to prevent silos from forming. It makes micro-management from the top very easy, but it also means that two or more parts of the company are not solving precisely the same problem.
The 12-inch MacBook's absurdly tiny main board and overall design is absolutely informed by the iPad. The engineering to created terraces of batteries in the MacBook will likely be used in future iOS devices. Apple bought a chip-design firm and continues to acquire technology around it so that it can use its own designs across its products.
The same companies, parts, and products lines make all of Apple's products, and all feed back together across them. While the iPad was secretly being designed in a lab for years before its release, the MacBook Air was strutting out there in public solving problems that led to solutions in a mobile device.
Apple does not drop everything to design new Macs. They fold in the lessons learned from everything they do to make new ones. The new Mac Pro's unique design--some love it, some think it looks like a fancy garbage can--did not gobble up massive resources at Apple. There is nothing in the hardware that pushed any envelopes; it was a design and manufacturing challenge of the sort Apple constantly solves. And it was a "gift" to developers and professional users, to show they were still thinking about them, which I will say more about in a moment.
As for software, you are not going to find me saying that all is rainbows and unicorns. However, because of the parallel trees of development across OS X and iOS, along with similar trees for its other products (the Airport Extreme Base Station and Apple TV, and so on), much of the work that goes into improving system releases is across platforms.
The issues that I and others complained in iOS 8 and Yosemite, some of them fixed since January, are at a higher level of software development, which consumes a much smaller percentage of the whole. Sometimes, it's presentation; sometimes interaction; sometimes cloud services. iCloud problems are not a Mac problem, although sometimes it's OS X that's at fault in a sync.
But software troubles are not solved by focus. They are solved by good management, good processes, and enough time. Apple rebuilt its management in 2012, leading to Jony Ive taking over interface development alongside industrial design. This resulted in two years of software turmoil, as fundamental engineering and top-level user experience was changed. We all cried out for a pause, and Apple's WWDC 2015 announcements of iOS 9 and El Captain (OS X 10.11) indicate it is ready, too: They are maintenance releases, with only one major new flagship feature--in iOS. (That would be simultaneous app usage on certain iPad models.)
Sign up for CIO Asia eNewsletters.